Addressing comment from Stoyan

Author: rodrigoareis

forgerock-authenticator/src/main/java/org/forgerock/android/auth/PushResponder.java

@@ -356,9 +356,18 @@ public void onResponse(@NotNull Call call, @NotNull Response response) {
                     }
                     listener.onSuccess(null);
                 } else if (response.code() == 400 && pushNotification.getPushType() == PushType.CHALLENGE) {
-                    // Number challenge failed — notification stays pending so the user can retry.
-                    listener.onException(new PushNumberChallengeException(
-                            "Number challenge failed: the selected number was incorrect."));
+                    String challengeMessage = "Number challenge failed.";
+                    try {
+                        if (response.body() != null) {
+                            JSONObject json = new JSONObject(response.body().string());
+                            String amMessage = json.optString("message", null);
+                            if (amMessage != null && !amMessage.isEmpty()) {
+                                challengeMessage = amMessage;
+                            }
+                        }
+                    } catch (IOException | JSONException ignored) {}
+                    Logger.warn(TAG, "Push 400 response for CHALLENGE notification: %s", challengeMessage);
+                    listener.onException(new PushNumberChallengeException(challengeMessage));
                 } else {
                     listener.onException(new PushMechanismException("Communication with " +
                             "server returned " + response.code() + " code."));

forgerock-authenticator/src/test/java/org/forgerock/android/auth/PushResponderTest.java

@@ -275,8 +275,35 @@ public void testShouldSignJWTCorrectly() throws Exception {
 
     @Test
     public void testReplyAuthenticationMessageNumberChallenge400() {
-        // AC (a): 400 on a CHALLENGE notification → PushNumberChallengeException with "incorrect"
-        //         message; notification stays pending=true, approved=false.
+        // AC (a): 400 on a CHALLENGE notification with AM JSON body → PushNumberChallengeException
+        //         surfaces AM's message; notification stays pending=true, approved=false.
+        server.enqueue(new MockResponse()
+                .setResponseCode(400)
+                .setBody("{\"code\":400,\"reason\":\"Bad Request\",\"message\":\"Number challenge predicate not met.\"}"));
+
+        PushNotification notification = null;
+        try {
+            notification = newChallengePushNotification();
+        } catch (Exception e) {
+            Assert.fail("Failed to build challenge notification: " + e.getMessage());
+        }
+
+        try {
+            PushResponder.getInstance(storageClient).authentication(notification, true, pushListenerFuture);
+            pushListenerFuture.get();
+            Assert.fail("Should throw PushNumberChallengeException");
+        } catch (Exception e) {
+            assertTrue(e.getCause() instanceof PushNumberChallengeException);
+            assertTrue(e.getLocalizedMessage().contains("Number challenge predicate not met."));
+            assertTrue(notification.isPending());
+            assertFalse(notification.isApproved());
+        }
+    }
+
+    @Test
+    public void testReplyAuthenticationMessageNumberChallenge400NoAmMessage() {
+        // AC (a2): 400 on a CHALLENGE notification with no body → fallback message used;
+        //          notification stays pending=true, approved=false.
         server.enqueue(new MockResponse().setResponseCode(400));
 
         PushNotification notification = null;
@@ -292,7 +319,7 @@ public void testReplyAuthenticationMessageNumberChallenge400() {
             Assert.fail("Should throw PushNumberChallengeException");
         } catch (Exception e) {
             assertTrue(e.getCause() instanceof PushNumberChallengeException);
-            assertTrue(e.getLocalizedMessage().contains("incorrect"));
+            assertTrue(e.getLocalizedMessage().contains("Number challenge failed."));
             assertTrue(notification.isPending());
             assertFalse(notification.isApproved());
         }